I had some at a BBQ last night just like 2, I couldn't eat it, lobbed it back on for a few minutes. But like I say, each to their own.
Because chicken and pork have parasites or bacteria that can make it to the centre of the meat, so if it's not cooked through you're at risk. Good quality steak is only likely to have bacteria on the surface, so seared on the outside and raw in the middle is fairly safe.
Fook, I had chicken in spain a few years that had blood in the middle. 'Es peligroso para comer' I told them in broken Spanish. And after that, 'No pago'.
Any potential food poisoning bugs are on the surface with Lamb or Beef hence why you can have it rare as you state, although the bloody Environmental Health Nazis are against this as they still want everything cremated, if you are offered rare pork in a restaurant as has become the fad run a mile, over 30 years in the catering industry so I would happily cook and serve a blue steak, pink lamb and usually have mine medium rare when it comes to steak.
2.5 for me, I like a nice line of pink through the middle. Making me want bloody miller and carter now
Rare or Medium Rare are my personal choice. To be honest though it mostly comes down to the quality of the meat. I've had steak medium but the quality has been so good its still banging. Anything over medium is just unacceptable and a waste of good food.